gtx480 or gtx295, Which is better?

I have installed a windows vista operating system on my computer and it has a support of an intel core i7920 powered by the zotec GTX295. PSU is of enermax1000w. Currently i am using the evga gtx295 and planning to buy a new one , How would be gtx480. Actually i want to buy gtx480 but will it make much changes in my system?

Here i have given you the specifications of GeForce GTX 295 as well as GeForce GTX 480 follows.
Specifications of GeForce GTX 295 :

1. CUDA Cores : 480 ( 240 per GPU )
2. Graphics Clock : 576 MHz
3. Processor Clock : 1242 MHz
4. Texture Fill Rate : 92.2 billion/sec
5. Maximum Digital Resolution : 2560x1600
6. Maximum VGA Resolution : 2048x1536
7. Standard Display Connectors : Two Dual Link DVI HDMI
8. Supports HDMI, Multi Monitor, HDCP, Audio Input for HDMI SPDIF
9. Memory Clock : 999 MHz
10. Standard Memory : 1792 MB GDDR3 ( 896MB per GPU )
11. Memory Interface Width : 896-bit ( 448-bit per GPU )
12. Memory Bandwidth : 223.8 GB/sec

Specifications of GeForce GTX 480 :

1. CUDA Cores : 480
2. Graphics Clock : 700 MHz
3. Processor Clock : 1401 MHz
4. Texture Fill Rate : 42 billion/sec
5. Memory Clock : 1848 MHz
6. Standard Memory : 1536 MB GDDR5
7. Memory Interface Width : 384-bit
8. Memory Bandwidth : 177.4 GB/sec
9. Maximum Digital Resolution : 2560x1600
10. Maximum VGA Resolution : 2048x1536
11. Standard Display Connectors : Mini HDMI Two Dual Link DVI
12. Support for Multi Monitor, HDCP , HDMI, Audio Input for HDMI.

I think GeForce GTX 480 would be better then the GeForce GTX 295 as there are much differences between their specifications. It is but obvious that GeForce GTX 480 for more higher graphics then the GeForce GTX 295 because Graphics Clock and Processor Clock of GTX 480 is much higher then the GTX 295. Graphics Clock of GTX 480 is 700 MHz where as it is 576 MHz in GTX 295. And Processor Clock of GTX 480 is 1401 MHz and same for the GTX 295 is 1242 MHz which makes much difference while playing the games in high graphics settings.

I would be recommending you to buy GeForce GTX 480 which has a better graphic support then the GTX 295. I have GTX 480 in my computer system and believe it can support even in high definition graphics with the highest game settings. But the only thing you need in your computer is a better fan which can cool it up faster as it might happen that your fan can not do it and which results in game crashing.